Simplify the following expression: $ t = -1 + \dfrac{-7r + 2}{9} $
Solution: In order to add expressions, they must have a common denominator. Multiply the first expression by $\dfrac{9}{9}$ $ \dfrac{-1}{1} \times \dfrac{9}{9} = \dfrac{-9}{9} $ Therefore $ t = \dfrac{-9}{9} + \dfrac{-7r + 2}{9} $ Now the expressions have the same denominator we can simply add the numerators: $t = \dfrac{-9 - 7r + 2}{9} $ $t = \dfrac{-7r - 7}{9}$